The invention relates to a vacuum tight brightness intensifier tube, comprising an envelope which is composed of a cylindrical sleeve portion which includes a radial supporting face for an entrance window at a first axial end, and a radial supporting face for an exit screen at a second axial end, said envelope accommodating an exactly positioned electron-optical imaging system. The invention also relates to the manufacture of such a tube.
A brightness intensifier tube of this kind is known from U.S. Pat. No. 4,171,480.
Assembly of such a tube usually requires many operations, for example the vacuum tight mounting of an exit window on a cylindrical wall portion, the mounting of an electron optical system in a bush thus formed, and the vacuum tight mounting of an entrance window. It is of essential importance that the electron optical system is exactly positioned and that distortion or contamination of the tube is prevented during the mounting of, for example, windows. In practice this implies a comparatively costly mounting procedure which often involves a comparatively high percentage of rejects.